Abstract. A photo-electric aerosol sensor, a diffusion charger, an Aethalometer, and a
continuous particle counter were used along with other real-time instruments
to characterize the particle-bound polycyclic aromatic hydrocarbon (p-PAH)
content, and the physical/chemical characteristics of aerosols collected a)
in Wilmington (CA) near the Los Angeles port and close to 2 major freeways,
and b) at a dynamometer testing facility in downtown Los Angeles (CA), where
3 diesel trucks were tested. In Wilmington, the p-PAH, surface area,
particle number, and "black" carbon concentrations were 4-8 times higher
at 09:00–11:00 a.m. than between 17:00 and 18:00 p.m., suggesting that during rush
hour traffic people living in that area are exposed to a higher number of
diesel combustion particles enriched in p-PAH coatings. Dynamometer tests
revealed that the p-PAH emissions from the "baseline" truck (no catalytic
converter) were up to 200 times higher than those from the 2 vehicles
equipped with advanced emission control technologies, and increased when the
truck was accelerating. In Wilmington, integrated filter samples were
collected and analyzed to determine the concentrations of the most abundant
p-PAHs. A correlation between the total p-PAH concentration (μg/m3) and the measured photo-electric aerosol sensor signal (fA) was
also established. Estimated ambient p-PAH concentrations (Average=0.64 ng/m3; Standard deviation=0.46 ng/m3 were in good agreement
with those reported in previous studies conducted in Los Angeles during a
similar time period. Finally, we calculated the approximate theoretical
lifetime (70 years per 24-h/day) lung-cancer risk in the Wilmington area
due to inhalation of multi-component p-PAHs and "black" carbon. Our
results indicate that the lung-cancer risk is highest during rush hour
traffic and lowest in the afternoon, and that the genotoxic risk of the
considered p-PAHs does not seem to contribute to a significant part of the
total lung-cancer risk attributable to "black" carbon.